This invention relates generally to apparatus for filtering large volumes of transport air having dust or other foreign matter entrained therein by passing such transport air through a plurality of self-cleaned filter elements, usually cylindrically shaped pleated paper filter elements.
Historically, industrial filters have been designed to filter and clean large volumes of air by utilizing a plurality of large fabric bags through which the dirty air flows and deposits the entrained foreign matter on the surface of the bags. The effective life of these so-called "baghouse" filters is extended considerably by periodically cleaning the bags, such as by mechanical shaking, by pulses of air or the reverse flow of pressurized air, whereby most of the foreign matter deposited on the bags is removed therefrom and allowed to fall by gravity into a collection hopper or the like.
In Frey U.S. Pat. No. 4,218,227, an improved industrial dust collector is disclosed in which compact pleated paper filter elements are substituted for the conventional bag filters. As explained in greater detail in such patent, the compact size of the pleated paper filter elements, as compared to the much larger cylindrical bags, resulted in a significant reduction in the overall size of the filter apparatus as a whole, assuming the same quantity of transport air is cleaned by both units. In the Frey dust collector and most of its progeny, the pleated paper filters are generally cylindrical in shape and are mounted to a partition plate to hang vertically downwardly therefrom. Since the filter elements depend vertically downwardly, the bottom ends of the filter must be blanked off or capped to prevent the upwardly moving transport air from entering the filter without passing through the filter media, and therefor the vertically disposed filter elements themselves reduce the available space for proper interstitial velocity of the transport air, whereby a larger overall dust collector housing must be provided to assure such proper interstitial velocity. Moreover, this type of dust collector usually suffered the disadvantage of requiring a relatively complex mounting arrangement for mounting the filter elements within the housing at a vertical disposition, and when the filter elements eventually had to be replaced, the usual practice was to shut the dust collector down for a considerable period of time so that a workman could enter the filter apparatus and manually remove and replace each filter element from inside the housing of the filter apparatus.
In an effort to overcome some of the aforesaid disadvantages of the conventional dust collector having pleated paper filter elements, it has been proposed to position such filter elements with a horizontal extent or at least generally horizontal extent, as compared with the vertical extent as disclosed in the Frey patent. Representative disclosures of such horizontal-type dust collectors may be found in Schuler U.S. Pat. No. 4,395,269, Browning U.S. Pat. No. 4,277,260, and Russian Patent 627841. The Schuler patent states that the dust collector disclosed therein, which includes generally horizontal positioning of the filter elements, results in a more compact dust collector that has a cleaning capacity of at least forty to fifty or more c.f.m. per cubic foot of volume, as compared with the typical vertically disposed filter elements. Advantages are also asserted to result from the downwardly slanted positioning of the filter elements, and the utilization of a baffle at the inlet of the dust collector which is struck by the particles of foreign matter entering the dust collector, to thereby prevent direct impingement of such foreign matter upon the uppermost filter elements and reduce wear on such filter elements. However, with this arrangement, a somewhat complicated mounting arrangement is provided for the filter elements, including a specially formed stepped mounting plate, a cantilevered yoke assembly for extending through the interior of each filter element to support it, and an end cap detachably mounted on the yoke by a bolt and handle. Moreover, the presence of the baffle at the inlet of the dust collector inherently interferes with the downward flow of the dust particles impinging thereagainst, whereby the relatively large particles tend to remain entrained in the transport air for cleaning by the filter elements rather than passing directly to the bottom of the dust collector for collection thereat without burdening the filter elements in a manner that can increase the pressure drop thereacross and/or require most frequent cleaning by the pulse jet cleaning apparatus.
In contrast to the devices discussed above, the present invention provides a dust collector or filtering apparatus which obtains all of the space saving advantages obtained from using horizontally disposed filter elements while also alleviating the aforesaid drawbacks associated with known apparatus.